COURTESY PHOTO | A photo of hunter Daniel Lamphere taken by a friend at Peconic Bay Medical Center’s emergency room shows injuries allegedly inflicted during an altercation in Mattituck in January.

Saying the forensic evidence did not support the charge, the Suffolk District Attorney’s office has dismissed the felony assault charge against former county police officer Jon Ferris, who was arrested in a field behind his Mattituck home in January and charged with beating an upstate hunter with his own shotun after the man had shot and killed Mr. Ferris’s dog.

A second and lesser charge against Mr. Ferris, illegally feeding deer, is scheduled for trial in Southold Justice Court on June 6.

In a statement issued Friday afternoon, Robert Clifford, a spokesman for District Attorney Tom Spota, said the decision to drop the assault case was based on “credibility issues.”

The hunter, Daniel Lamphere of Rennsaeler, N.Y., “gave conflicting accounts of the incident which were not supported by the forensic evidence,” Mr. Clifford said. “This office determined this case could not be proven beyond a reasonable doubt.”

That decision “is unbelievable and should be investigated,” said George Duell of East Berne, N.Y., Mr. Lamphere’s hunting partner that day.

“I can’t believe that a man could beat another man almost to death and get away with it,” he said. “Forensic evidence? It’s there. He split his head wide open.”

Mr. Duell charged that Mr. Ferris received preferential treatment because of his law enforcement background.

“Because this guy was a cop he walked,” he said. “He must have a lot of pull down there.”

Mr. Lamphere was deer hunting south of the Farmveu community on Jan. 26 when he said he was approached by three dogs. He managed to shoo two away but claims the third lunged at him. He fired a single shot at the animal, a German shepherd named Bear, killing it.

He told police that Mr. Ferris, the dog’s owner then came up to him with a pistol drawn, wrestled the shotgun from him and struck him multiple times on the head with the butt stock.

The Mattituck Fire Department rescue squad brought the 63-year-old Mr. Lamphere to Peconic Bay Medical Center, where ER doctors used 12 staples to close the wounds.

“I was struck seven or eight times,” Mr. Lamphere told The Suffolk Times at the time. “It was a nightmare.”

The DA’s office has not ended its prosecution against Mr. Lamphere, who was charged in April with a misdemeanor count of fourth-degree criminal possession of a weapon. A conviction carries up to a year in jail. As a convicted felon, it is unlawful for Mr. Lamphere to possess firearms. In 1994 he served jail time on an attempted drug possession. conviction.

He was also charged by the state Department of Environmental Conservation with firing a weapon within 500 feet of an occupied dwelling and hunting without the landowner’s permission.